Astronauts spend six months regularly during their rotating missions aboard the International Space Station.
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According to new research, spaceflights lasting six months or longer take a toll on astronauts’ brains, and crew members may need to wait at least three years before returning to space.
The scientists compared the brain scans of 30 astronauts before their two-week, six-month or year-long spaceflights with scans taken after they returned to Earth. Scans revealed that the ventricles, or cavities within the brain filled with cerebrospinal fluid, expanded greatly within the brains of astronauts who went to the International Space Station on missions lasting at least six months.
The findings have implications for future, long-term missions as NASA and its international partners aim to establish a sustainable human presence on the Moon with Artemis programwith the aim of sending people to Deep space destinations such as Mars. A study detailing the findings was published Thursday in the journal Scientific reports.
Cerebrospinal fluid provides protection and nourishment to the brain while removing waste products. But when astronauts go into space, fluids inside the body build up toward the head and push the brain up toward the skull, causing the ventricles to expand.
“We found that the more time people spent in space, the larger their ventricles,” Rachel Seidler, a professor of physiology and kinesiology at the University of Florida, said in a statement. “Many astronauts travel to space more than once, and our study shows that it takes about three years between flights for the ventricles to fully recover.”
Eight of the astronauts in the study went on two-week missions, while 18 ventured on six-month missions. Four astronauts had missions that lasted about a year. During the analysis, the researchers determined that the degree of enlargement of the ventricles varied depending on how long the astronauts had been in space.
“The biggest jump comes when you go from two weeks to six months in space,” said Seidler, who is also a member of UF Health’s Norman Vicks Institute of Neurological Diseases.
There was no further increase between six months and one year, Seidler said, meaning that ventricular hypertrophy appeared to wane after six months, which surprised the researchers. “This is good news for future Mars travelers who may end up spending (approximately) two years in microgravity.”
And the effect was negligible for astronauts on two-week trips into space — a positive finding for the commercial space industry such as Increasing short-term space tourism trips in popularity.
“People who spend only two weeks show little or no change in these structures,” Seidler said. “This is good news for those going on short space missions.”
For 11 astronauts, all of whom had more than three years to recover between missions, the researchers noted an increase in ventricular volume after each of their most recent missions. Seven astronauts who had a shorter recovery period between missions showed slight ventricular hypertrophy after their last flight.
While this result seems positive, it indicates that the brains of seasoned astronauts have ventricles that remain enlarged before their next mission and “have less available space or compliance with ventricular expansion with spaceflight,” the authors wrote in the study.
Scientists don’t know how long it takes for the ventricles to fully recover after spaceflight, but their analysis showed that astronauts experienced a 55% to 64% recovery toward preflight levels six to seven months after a six-month mission to the space station. .
Based on the research results, the team concluded that astronauts needed at least three years between missions to allow their ventricles to fully recover.
The findings could be used as NASA and other space agencies plan future missions, but Seidler said more research is needed. I’ve begun work on a new project looking at long-term health and recovery up to five years after six-month spaceflights.
“We don’t yet know for sure what the long-term consequences of this will be for the health and behavioral health of space travelers, so allowing the brain time to recover seems like a good idea,” she said.
“The results may indicate that three years are needed for recovery. However, astronauts have highly specialized skills and training and there may be a rationale for including them on additional missions before this time.”
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